Automatic changer for digital discs

Abstract

An automatic changer for playing digital discs containing music or other digitally encoded information has a loading station, a play station and a discard station. A robot arm individually engages the top disc of a stack of discs stacked at the loading station through the center hole in the disc and lifts and transports the disc to the play station where it lowers the disc over a reading head for play. After play, the robot arm raises the disc from the play station and transports the disc to the discard station and releases it there. In an alternative embodiment, a carousel containing a plurality of discs rotates sequentially to position the discs over the reading head. When changing discs the carousel is lifted to raise a played disc from the reading head, rotated to position the next disc to be played over the reading head and lowered to lower the disc to be played into playing position.

What is claimed and desired to be secured by Letters Patent of the United States is: 
     
       1. A digital disc changer, comprising: a loading station having means for receiving a plurality of digital discs in a stacked relationship to form a loaded stack of discs to be played;   a play station having means for sequentially playing discs from said stack;   a discard station having means for receiving in a stacked relationship discs that have been played at said play station;   means for sequentially transporting the top disc from the stack of discs to the play station and then to said discard station to thereby stack the played discs in a stack at the discard station with the last-played disc being stacked on the top of any discs present at the discard station wherein said transporting means includes means for sequentially raising to a raised position the top disc from said loaded stack of discs and transporting said disc to said play station, lowering to a lowered position said disc at said play station for play, raising to the raised position said disc from said play station after play and transporting it to the discard station and lowering and releasing said disc at said discard station, wherein said transporting means includes means for lowering said disc to an intermediate position during transport thereof between stations and means associated with each station for registering said transporting means with each associated station when said disc is in the intermediate position.   
     
     
       2. A digital disc changer as recited in claim 1, wherein said transporting means includes a rotatably mounted driving member having a cam member thereon that is operative to raise and lower said disc upon rotation of said driving member. 
     
     
       3. A digital disc changer as recited in claim 2, wherein said transporting means includes a driven member frictionally engaging said driving member, said driven member being operative to cause said transporting means to transport said disc between stations. 
     
     
       4. A digital disc changer as recited in claim 3, wherein said driving member is operative to rotate with respect to said driven member when said transporting means is registered at one of said stations by said registering means. 
     
     
       5. A digital disc changer as recited in claim 1, wherein said transporting means includes means including a rotatable cam member for raising and lowering a disc as it is transported from station to station. 
     
     
       6. A digital disc changer, comprising: means at a play position for playing back information recorded on a digital disc; and   means for transporting a disc from a first position to the play position and then to a second position, said transporting means including means for sequentially lifting the disc from said first position, transporting the disc to the play position, lowering the disc at the play position, lifting the disc from the play position, transporting the disc to the second position and lowering the disc at the second position; wherein said transporting means includes a carousel and wherein said transporting means is operative to raise and lower said carousel to thereby raise and lower said disc.   
     
     
       7. A digital disc changer for sequentially playing a plurality of digital discs, comprising: a loading station having means for receiving a plurality of digital discs in a stacked relationship to form a stack of discs to be played;   a play station having means for sequentially receiving and playing discs from said stack;   a discard station having means for receiving discs from said play station; and   means including a robot arm for lifting a disc from the top of said stack, transporting the disc to the play station and lowering it at the play station for play, lifting the disc from the play station after play, transporting the disc to the discard station and releasing the disc at the discard station and wherein each of said digital discs has a central aperture and wherein said robot arm includes means for engaging said aperture for lifting and transporting said disc, wherein said robot arm is driven via a clutch having a driving member and a driven member frictionally engaging said driving member wherein said driving member includes means for raising and lowering said robot arm upon rotation of said driving member.   
     
     
       8. A digital disc changer as recited in claim 7, wherein said robot arm moves in a circular motion and has an axis of rotation disposed equidistant from said loading station, said play station and said discard station. 
     
     
       9. A digital disc changer as recited in claim 7, wherein said raising and lowering means includes a cam. 
     
     
       10. A digital disc changer as recited in claim 7, wherein said driven member is mechanically coupled to said robot arm and is operative to move the robot arm. 
     
     
       11. A digital disc changer as recited in claim 10, wherein said driving member makes a single complete revolution each time a disc is transported between two adjacent stations. 
     
     
       12. A digital disc changer as recited in claim 11, wherein a disc is moved from the play station to the discard station and another disc is moved from the loading station to the play station during a changing cycle, and wherein said driven member is rotated a single complete revolution during the changing cycle. 
     
     
       13. A digital disc changer as recited in claim 12 further including means for registering said robot arm at each of said stations. 
     
     
       14. A digital disc changer as recited in claim 11, wherein said robot arm is rotated a single complete revolution during a changing cycle. 
     
     
       15. A digital disc changer as recited in claim 14, wherein said driving member is rotated three complete revolutions during a changing cycle. 
     
     
       16. A digital disc changer for sequentially playing a plurality of digital discs, comprising: a loading station having means for receiving a plurality of digital discs in a stacked relationship to form a stack of discs to be played;   a play station having means for sequentially receiving and playing discs from said stack;   a discard station having means for receiving discs from said play station; and   means including a robot arm for lifting a disc from the top of said stack, transporting the disc to the play station and lowering it at the play station for play, lifting the disc from the play station after play, transporting the disc to the discard station and releasing the disc at the discard station and wherein each of said digital discs has a central aperture and wherein said robot arm includes means for engaging said aperture for lifting and transporting said disc,   wherein said engaging means includes one or more engaging members that frictionally engage said central aperture and are resiliently biased to exert a outwardly directed radial force against said disc;   wherein said loading station includes an elongated stacking spindle about which discs may be stacked, said spindle being mounted for movement along its longitudinal axis and resiliently biased to an extended position wherein said spindle enters the central aperture of a disc, said spindle being movable along its longitudinal axis by said pick-up head to a retracted position out of said central aperture to permit said engaging members to engage said central aperture;   wherein said discard station includes means for urging said engaging member or members sufficiently inwardly to disengage said central aperture and release said disc; and   wherein said discard station includes a discard spindle about which discs are discarded, wherein said engaging member urging means includes a surface on said discard spindle that engages said engaging member or members to disengage said disc when said robot arm is positioned at the discard station.   
     
     
       17. A digital disc changer, comprising: a loading station having means for receiving a digital disc to be played;   a play station having means playing discs from said loading station;   a discard station for receiving a digital disc played at the play station; and   transporting means for transporting digital discs from the loading station to the play station and from the play station to the discard station, the transporting means includes means for raising said disc to a raised position at said loading station and transporting the disc to the play station and lowering the disc to a lowered position at the play station, wherein said loading station, play station, and discard station are arranged in a cyclic path around a central axis and the transporting means includes driving and driven members in frictional engagement with each other to form a friction clutch and the raising and lowering means includes cam means whereby relative rotational movement between the driving and driven members is translated by the cam means into a raising and lowering of the transporting means.   
     
     
       18. A digital disc changer as recited in claim 17, wherein said raising, lowering and transporting means includes a robot arm. 
     
     
       19. A digital disc changer as recited in claim 17, wherein said raising, lowering and transporting means includes a carousel. 
     
     
       20. A digital disc changer as recited in claim 17, wherein said changer includes said discard station and wherein said raising, lowering and transporting means includes means for transporting said disc from said play station to said discard station. 
     
     
       21. A digital disc changer, comprising: means for playing a digital disc;   a carousel having a plurality of radially spaced receptacles for receiving a plurality of digital discs; and   means for raising, rotating and lowering said carousel to raise each of said discs, sequentially transport them to said playing means and lower them over said playing means for play thereby, and to raise them from said playing means after play and transport them away from said playing means.   
     
     
       22. A digital disc changer as recited in claim 21 further including means positioned over said disc for retaining the disc being played over the playing means. 
     
     
       23. A digital disc changer as recited in claim 22, wherein said retaining means includes means for magnetically retaining disc. 
     
     
       24. A digital disc changer as recited in claim 22, wherein said retaining means includes a rotatable head for resiliently retaining said disc. 
     
     
       25. A digital disc changer as recited in claim 22 further including means for raising said retaining means in unison with said carousel. 
     
     
       26. A digital disc changer as recited in claim 22 further including means for lowering said retaining means in unison with said carousel. 
     
     
       27. A digital disc changer as recited in claim 22, wherein said carousel raising means includes a rotatable cam member. 
     
     
       28. A digital disc changer as recited in claim 22, wherein said carousel raising and lowering means includes means for lowering said carousel to an intermediate position during rotation thereof and means associated with said playing means for registering one of said discs with said playing means when said carousel is in the intermediate position. 
     
     
       29. A digital disc changer as recited in claim 28, wherein said carousel raising means includes a rotatably mounted driving member having a cam member thereon that is operative to raise and lower said carousel upon rotation of said driving member. 
     
     
       30. A digital disc changer as recited in claim 28, wherein said transporting means includes a driven member frictionally engaging said driving member, said driven member being operative to cause said carousel to rotate. 
     
     
       31. A digital disc changer as recited in claim 30, wherein said driven member is said carousel. 
     
     
       32. A digital disc changer as recited in claim 30, wherein said driving member is operative to rotate with respect to said driven member when said carousel means is registered by said registering means. 
     
     
       33. A digital disc changer as recited in claim 30, wherein there is slippage between said driven member and said driving member when said driving member is driven while said carousel is registered. 
     
     
       34. A digital disc changer as recited in claim 21 further including means for registering said carousel at said playing means. 
     
     
       35. A digital disc changer as recited in claim 21, wherein said carousel is driven via a clutch having a driving member and a driven member frictionally engaging said driving member wherein said driving member includes means for raising and lowering said carousel upon rotation of said driving member. 
     
     
       36. A digital disc changer as recited in claim 35, wherein said raising and lowering means includes a cam. 
     
     
       37. A digital disc changer as recited in claim 35, wherein said driven member is mechanically coupled to said carousel and is operative to rotate the carousel about its axis of rotation. 
     
     
       38. A digital disc changer as recited in claim 37, wherein said driving member makes a single complete revolution each time a disc is transported to said playing means. 
     
     
       39. A digital disc changer, comprising: a play station having means for reading information recorded on a digital disc;   a loading station; and   a transport mechanism having means for lifting a disc at the loading station, transporting it to the play station by rotating the disc about an axis and lowering the disc at the play station along a path parallel to said axis and wherein said transport mechanism includes a carousel.   
     
     
       40. A digital disc changer as recited in claim 39, wherein said transport mechanism includes a rotatable cam. 
     
     
       41. A digital disc player, comprising: means at a loading position for receiving a plurality of discs in a stacked relationship;   a play position;   transporting means including a robot arm provided with means for engaging a top one of said discs at the loading position, transporting the disc to the play position, centering and rotatably retaining the disc in a centered relationship at the play position; and wherein said transporting means includes a cam and clutch assembly for rotating said robot arm between said loading and play positions.   
     
     
       42. A digital disc changer as recited in claim 41, wherein said centering and retaining means includes means for resiliently retaining said disc. 
     
     
       43. A digital disc changer as recited in claim 41, wherein said centering and retaining means includes means for magnetically retaining said disc. 
     
     
       44. A digital disc reader or writer comprising: means for rotating at a reading or writing position an individual disc capable of containing digital information;   means at a loading station for receiving a plurality of discs in a stacked relationship; and   means for engaging a top one of said discs at said loading station at or near the center thereof and transporting said disc to said reading or writing position for rotation by said rotation means, said engaging means being operative to center and retain said disc for rotation at said reading or writing position and said engaging means rotating with said disc; and wherein said transporting means includes a robot arm.   
     
     
       45. A digital disc reader or writer comprising: means for rotating at a reading or writing position an individual disc capable of containing digital information;   means at a loading station for receiving a disc to be read or written; and   transporting means including a robot arm provided with means for engaging a disc at said loading station at or near the center thereof and transporting said disc to said reading or writing position for rotation by said rotating means, said engaging means being operative to center and retain said disc for rotation at said reading or writing position and said engaging means rotating with said disc; and wherein said robot arm is driven from said loading station to said reading or writing position and said transporting means includes cam member to raise and lower said robot arm.   
     
     
       46. A digital disc changer as recited in claim 45, wherein said centering and retaining means includes means for resiliently retaining said disc. 
     
     
       47. A digital disc changer as recited in claim 45, wherein said centering and retaining means includes means for magnetically retaining said disc. 
     
     
       48. A digital disc changer comprising: a play station having means for reading information recorded on a digital disc;   a loading station; and   a transport mechanism having means for lifting a disc at the loading station, transporting it to the play station by rotating the disc about an axis and lowering the disc at the play station along a path parallel to said axis, wherein said transport mechanism includes a carousel.   
     
     
       49. A digital disc changer comprising: a loading station having means for receiving a digital disc to be played;   a play station having means for reading information recorded on a digital disc;   a discard station for receiving a digital disc from the play station; and   transporting means for transporting a digital disc from the loading station to the play station and from the play station to the discard station, the transporting means including means for raising said disc to a raised position at said loading station and transporting the disc to the play station and lowering the disc to a lowered position at the play station and means for lowering said disc from said raised position to an intermediate position during transport thereof between stations and means associated with each station for registering said transporting means with each associated station when said disc is in the intermediate position.   
     
     
       50. A digital disc changer as recited in claim 49 wherein said transporting means includes a robot arm. 
     
     
       51. A digital disc changer as recited in claim 49 wherein said transporting means includes a carousel. 
     
     
       52. A digital disc changer comprising: means at a play position for playing back information recorded on a digital disc; and   means for transporting a disc from a first position to the play position and then to a second position, said transporting means including means for sequentially lifting the disc from said first position, transporting the disc to the play position, lowering the disc at the play position, lifting the disc from the play position, transporting the disc to the second position and lowering the disc at the second position, wherein said transport mechanism includes a carousel.   
     
     
       53. A digital disc changer as recited in claim 52 wherein said transporting means includes driving and driven members in engagement with each other to form a clutch and the raising and lowering means includes cam means whereby relative movement between the driving and driven members is translated by the cam means into a raising and lowering of the transporting means. 
     
     
       54. A digital disc changer as recited in claim 52 wherein said transporting means includes a rotatable cam.